Chứng tỏ rằng với mọi số tự nhiên n, tích (n + 7) (n + 8) luôn chia hết cho 2

Chứng tỏ rằng số có dạng aaa là bội của 37

Tìm số tự nhiên x

45 là bội của x-2

1. It's a serious problem. I don't know how it......(can/solve)

2. The teacher ordered Tom......(go) to the blackboard

3. I learn to swim when i......(be) very young. I......(teach)by my father

4. There is somebody walking behind us. I think we......(follow)

5. My grand was a builder. He........(build) this house many years ago

1. The rice-cooking festival......(hold) every two years

2. It's a big factory. Five hundred people......(employ) there

3. The letter.......(post) a week ago and it.......(arrive) yesterday

4. Water......(cover) most of the Earth's surface

5. The boat......(sink) quickly but fortunately everybody......(rescue)

6. The gate....(look) at 6:30 pm every day